It is known to provide a dip tube in a water heater to supply cold water to the tank. The cold water is injected at the bottom of the tank through the dip tube. The cold water is then heated where it rises in the water heater and is drawn off by a hot water discharge pipe. A pipe nipple connects to the water heater, the water heater being made from steel, and allows plumbing for the cold water inlet to be connected to the water heater. The pipe nipple is threaded on both ends and is typically made of brass, galvanized steel, or galvanized steel with a dielectric insert.
Although the exterior of galvanized nipples are dielectrically compatible with the steel water heater, the interior of the galvanized nipple is not. With the interior unprotected, the galvanized nipple corrodes, clogs, rusts and eventually leaks. Brass nipples, on the other hand, internally will not corrode like galvanized nipples, but the introduction of brass to the steel water heater is not a dielectrically correct connection. Left unprotected, the area of the steel water heater below the brass nipple corrodes. Therefore, a dielectric connection is desired because it prevents electrolysis with the connecting plumbing and the steel water heater.
To combat the corrosion issue and provide a dielectric connection, water heater manufacturers are now supplying plastic lined galvanized nipples with new water heaters. This plastic liner in the galvanized nipple is also known as the dielectric liner. These plastic lined galvanized nipples are sometimes referred to as dielectric nipples. The dielectric nipples and the brass nipples cost more than the galvanized steel nipples.
As noted above, the pipe nipple is threaded on both ends, where one threaded end connects to the water heater via a coupling and the other threaded end connects to the plumbing. The dip tube is located below the threaded end of the pipe nipple that connects to the water heater. The dip tube typically rests within the coupling but requires a gasket and a dip tube cup to retain the dip tube therein. The dip tube cup is also known as a retaining cup. The dip tube, the dielectric liner, the gasket and the dip tube cup are separate components that must be assembled or disassembled during installation and/or service of the water heater. This results in increased amounts of labor for verification of both the proper assembly and efficient functionality of each separate component. This increased labor results in increased costs for the manufacturer and servicemen which are typically passed on to the consumer. Moreover, improper installation of these separate components can result in leaks, which may form between the dip tube and the pipe nipple. As a result of the above, there is a need to reduce the labor and costs associated with the assembly and repair of a dip tube for a water heater and to provide a leak free dip tube.
It is also known for a dip tube to have a plurality of holes drilled or punched in the side of the dip tube near its bottom to disperse the cold water at the bottom of the water heater. After the holes are drilled or punched, the opening at the bottom of the dip tube is melted to close the bottom by a heat sealing process. The drilling or punching of the holes may not be dimensionally accurate due to the inaccuracy of the tools used for drilling or punching as well as operator error. This dimensional inaccuracy of the holes creates uneven dispersion of the cold water at the bottom of the water heater which increases the mixture of cold water with the hot water in the water heater and increases heat loss. The heat sealing process creates inconsistent results and requires an expensive piece of equipment. The extensive labor involved in drilling or punching the holes and subsequent melting of the bottom of dip tube increases the overall costs associated with the dip tube. Thus, there is also a need to reduce the labor and costs associated with the manufacture of the bottom of the dip tube for dispersing the cold water near the bottom of the water heater.
What is disclosed is a dip tube for use with a water heater having a pipe nipple, the dip tube comprising:
an upper end and a tubular body, the upper end being located above the tubular body;
the upper end having an outer wall, a top portion and bottom portion, the upper end comprising:                a flange located at the top portion, the flange extending outwardly from the outer wall for retaining the dip tube at the nipple;        a reinforced connecting portion located at the bottom portion for connecting the upper end to the tubular body, where a portion of the tubular body is located within the reinforced connecting portion.        
The reinforced connecting portion maintains the position of the tubular body in the absence of a gasket and a retaining cup. The upper end may be overmolded onto the tubular body or mechanically attached to the tubular body. The dip tube may include a spacer for guiding and locating the upper end during insertion into the pipe nipple. The spacer may include plurality of ribs extending axially along the outer wall of the upper end.
The dip tube may further include a heat trap assembly that is integral with the upper end. The heat trap assembly may include at least one annular groove located on the outer wall of the upper end and having a circumferential slot andat least one heat trap having an outer ring portion, an inner portion, a partial circular slot and a connecting portion connecting the outer ring portion to the inner portion between the partial circular slot. The outer ring portion may located within the at least one annular groove and the inner portion extends through the partial circular slot and is located within the tubular body.
The dip tube may include a lower end connected to the tubular body. The lower end may include a top end, a bottom end, an outer wall, an inner wall and a bottom wall. The lower end may further include a plurality of openings to slow and disperse the flow of water from the tubular body into the water heater and a portion of the tubular body may be within the top end of the lower end.
The lower end may be overmolded onto the tubular body or mechanically attached to the tubular body. The lower end may be generally cylindrical. The outer wall of the lower end may include opposing flattened portions.
The plurality of openings may be maximized to slow and disperse the flow of water from the tubular body into the water heater and the material is minimized between the plurality of openings for the lower end to be structurally sufficient during use within the water heater.
The dip tube may include cylindrical portions located on either side of the flattened portions on the lower end, and the plurality of openings may include circular openings on the flattened portions and D-shaped openings on the cylindrical portions.
The the D-shaped openings may include a first set of openings positioned adjacent a second set of openings, and the straight portions of the D-shaped openings may bee proximal one another and the curved portions of the D-shaped openings may be distal each other.
What is disclosed is a combination of a dip tube and a pipe nipple for use with a water heater, the combination comprising:
a pipe nipple having a top portion, a bottom portion, an upper threaded end at the top portion and a lower threaded end at the bottom portion; and
a dip tube comprising:                an upper end and a tubular body, the upper end being located above the tubular body;        the upper end having an outer wall, a top portion and bottom portion, the upper end comprising:                    a flange located at the top portion, the flange extending outwardly from the outer wall for retaining the dip tube at the nipple;            a reinforced connecting portion located at the bottom portion for connecting the upper end to the tubular body, where a portion of the tubular body is located within the reinforced portion;                        
where the flange of dip tube is located on the upper threaded end at the top portion of the pipe nipple.
The combination of the dip tube and pipe nipple may include a coupling for attaching the pipe nipple to the water heater, where the combination is free of a gasket and a retaining cup and where the pipe nipple is free of an integrally attached dielectric liner and a separate heat trap assembly.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more detailed descriptions of particular embodiments of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention.